T Minus Sixty Days

A project log for Mr Robot Badge

Creating hardware, and 'gonzo trade journalism'

benchoffBenchoff 05/25/2017 at 17:290 Comments

In two months, I'm going to be holed up in a hotel room in Vegas, overlooking the god damned Ferris wheel, frantically packing electrostatic bags with badges, lanyards, stickers, batteries, and fidget spinners. I should be concerned, but I'm not. I have this pretty much under control.

Failures from the last revision

There were two problems with the "final" hardware revision. First: the power supply sucked. The power supply for this badge is four AA batteries delivering 3V to a TI switching regulator. The spec for this regulator says it can deliver 1.2A, which it probably could, if you use an inductor that costs $3 in quantity one. Unfortunately, I used one of the 'recommended' inductors from the application notes. I can get maybe 300 mA out of this regulator before it shuts down. This is a problem, because we're blinking a lot of lights and sending WiFi packets everywhere. This requires power.

Luckily, the firmware engineer for this project turned down the brightness of the LEDs (a handy feature of the charlieplex driver) and spent a few days pinging the badge while displaying IPs on the LEDs. Everything works. The bug is now a feature: we chose a shitty inductor on purpose so the battery lasts a long time. Sure. That's the story we're going with.

Second problem: the badge shorted out when I pressed the right button. Guess why?

Yeah, that was stupid as hell, but it's fixed now.


From the get go, this had to be an amazing looking badge. Generally, there are two ways you can go with this. You can either throw a ton of blinky LEDs on it, or you can put a lot of time into the art of the board. Take a look at last year's Queercon squid badge for an example of the latter.

One thing that hasn't been popularized is a custom color soldermask. Usually, boards are one of five colors: Green, Red, Blue, White, or Black. I wanted something different. The Mr. Robot Badge was designed around skin tone soldermask, with two colors of silk screen. It's simple, but effective.

Now, after some talks with Seeed (they're great, really), I have the first proof that custom color soldermask and weird silkscreens actually work

This is really, really fantastic. I couldn't have hoped for anything better.

And now I have to build five hundred of them...

Boards will be ordered from Seeed this week, and I have a Mouser cart with $1500 worth of stuff in it. Assembly? I have that taken care of. I know a guy. After that, it's a lot of programming badges, sticking them in bags, and shipping them off to somebody in Vegas.

Until this point, the reality of getting this project done was up in the air. This is a lot of fucking work, and a lot of fucking money to spend on something that might not happen. Until a week ago, I didn't even know if this custom soldermask / multiple silk process was possible.

Now, everything is lining up. I'm on time, under budget, and I even had a bit of money left over for some awesome (ly terrible) swag. This is it. This is the time when this project starts becoming real. It's only taken nine months and thousands of dollars so far, but here we are.